Process of spinning



Patented June 30, E942 raoosss or Delaware No Drawing. Application November 23, 1938, Se-

ria 1937 4 Claims.

'manner indicated above.

Another object is to provide a new cellulosic spinning solution of the viscose class from which products possessing very desirable characteristics may be obtained.

A still further object is'to provide a bath, or coagulating medium, which may be used in order to secure-a yarn suitable for use in the manufacture of rugs and the like.

These and other objects of my present invention will be clearly discernible from a perusal of the following description and appended claims.

The cellulosic wool industry, in which use is made of artificial staple fiber and the like, has developed to such an extent that staple fibers possessing characteristics peculiarly adapted for certain industries have been evolved. The present application will discuss, disclose and claim certain improvements in staple fiber production by which fibers peculiarly adapted for use in the manufacture of carpets and the like have been developed.

Among the several methods which have thus far been developed for the manufacture of artificial wool there is that process in which warn is spun and while yet undecomposed is collected on a spool, cut into lengths suitable for sliver production while still on the spool, acidifying the fibers so cut, opening, and then treating the fibers. This field of artificial wool production has gone through certain stages of development until now it is possible to produce a staple fiber yarn which is full-bodied, thoroughly curled and neither felted nor sticky if certain working conditions are observed. These working conditions bear certain relationships to the composition and the maturity of the viscose, and the composition of the spinning and the acidifying bath.

In this particular art it is a known fact that a thoroughly matured viscose maybe precipitated into a so-called water-soluble artificial silkthread by means of a spinning bath containing i No. 241,958. In Germany November 23,

(on. z t-st) To obtain such threads a spinning bath high in salt and low in acid content, for example, 300-350 grams per liter of sodium sulphate and 50 grams or less per liter of sulphuric acid, must be employed, provided that the viscose is permitted to mature long enough. If the water-soluble thread thus prepared is cut into staple lengths and then acidified, a curled wool is obtained, but that wool is only slightly full-bodied, and is also sticky and felted. If it is undesirable that stickiness develop, an increase in the sulphuric acid content of the bath up to 50-100 grams per liter may be employed. The resulting product, however, does not become essentially more full-bodied, it is felty, and the filaments which correspond to the spinnerette openings remain visible. Such products require a strong carding and thereby lose a part of the curling and the adhering property.

Unexpectedly I have discoveredthat iti's possible to obtain a thoroughly curled wool which at the same time is unfelted, full-bodied and can easily be carded, and in which the filaments corresponding to the spinnerette openings hardly appear. I accomplish this by employing or using a viscose of low alkali content, said viscose containing, for example, only 5% alkali with 8% cel lulose and having matured, at the same'time, to a ripeness of 3 to 1 Hottenroth. This cellulcsic alkaline in character.

solution is then spun by ordinary methods into a spinning bath containing much salt, for example, 250-350 or more grams per. liter of sodium sulphate, only a small amount of sulphuric act. (0 to 30 grams per liter) being used.

The yarn thus produced is still water-soluble, and is cut into any lengths desired. These yarns before cutting are subjected to the necessary stretching operations. After cutting the staple fiber lengths are loosened either by pulling .them apart or otherwise opening them mechanically. The fibers are then subjected to the action of a regenerating or fixing bath of a strength not to exceed 50 grams per liter of sulphuric acid, for example, 10-20 grams per liter. The fibers thus produced are processed in the usual manner.

I have also discovered that the first bath containing large amounts of salts need not necessarily be acidic at all but may even be neutral or slightly I may substitute for sodium sulphate or I may even use with sodium sulphate other salts, for example, magnesium sulphate, zinc sulphate or other known spinning bath ingredients. v

Viscoses with a relatively higher alkali content, that is, exceeding 6% alkali with 8% cellulose produce unsatisfactory results. My low alkali ture with wool. They are particularly suitable for use in the carpet industry, because they adhere well in coarse single titers of 20, 30 or more due to the disposition of their surfaces and on account of the thorough curling in the linkage of the tissue.

In order that the working of my new process may be more clearly understood the following examples are given:

Example 1 An alkali cellulose produced from cellulose usu ally employed in the manufacture of artificial silk is aged for '72 hours and then converted into a viscose with 8% cellulose and 5% alkali. This viscose is allowed to mature down to a Hottenroth degree of 3 and then spun using ordinary spinning nozzles in a spinning bath at 45 C. containing 300 grams per liter of sodium sulphate and 10 grams per liter of sulphuric acid. A stretch of from 60 to 80% may be imparted to the thread. The greenish brown threads thus produced, which are water-soluble, are then led together into a cable and introduced into a cutting machine which is to cut them into the de- A sired staple lengths. These staple lengths are then loosened, pulled apart or, otherwise mechanically opened, and in this state they are introduced into an acidifying bath which contains 10 grams per liter of sulphuric acid. After the developmentof gas is over and the fibers are entirely decomposed the acidifying liquid is discharged and the fibers are afterwards washed, desulphurized, bleached, soaped, dried and willowed, in the usual manner. The cellulosic wool thus obtained is wool-like, full-bodied, heavily curled, not sticky and is unfelted, the filaments having separated are hardly visible.

Example 2 The viscose described and set forth in Example 1 is matured to a maturity of 15 Hottenroth and then is spun in a similar way as in Example 1 except that the spinning bath contains 350 grams per liter of sodium sulphate and 2 grams per liter of soda lye. The yet water-soluble green brown shreds of cellulosic wool are stirred in a salt bath with 300 grams per liter of sodium sulphate whereby the shreds fall apart. The bath is discharged and the yet water-soluble fibers are introduced into the acidifying bath containing 20 grams per liter of sulphuric acid.

Example 3 Same as set forth in Example 1 except that a viscose with 9% cellulose and 6% alkali is used and that the acidifying bath contains 30 grams 6:!

per liter of sulphuric acid. Example 4 Same as set forth in Example 1 using, however,

a viscose with 7% cellulose and 4% alkali at a maturity of 1.2 Hottenroth.

Having thus described my invention as required by the patent statutes, what I claim is:

1. A process of producing curled, unfelted, fullbodied staple fibers which comprises extruding a viscose solution having a cellulose content of about 8% and an alkali content of about 5% and having a ripeness of about 3 to 1 degrees Hottenroth through a spinning nozzle into an aqueous spin bath containing about 250 to 350 grams per liter of soluble salts at a temperature of about 45 C. to form a water-soluble cellulose xanthate thread, cutting said thread into staple fibers of cellulose xanthate, mechanically opening said fibers, introducing said fibers into an acidifying bath containing about 10 to 50 grams per liter of sulphuric acid to decompose said xanthate fibers directly into curled, unfelted, full-bodied staple fibers of regenerated cellulose and then after-treating said fibers.

2. A process of producing curled, unfelted, fullbodied staple fibers which comprises extruding a viscose solution having a cellulose content of about 8% and an alkali content of about 5% and having a ripeness of about 3 degrees Hottenroth through a spinning nozzle into a spin bath containing about 300 grams per liter of sodium sulphate and about 10 grams per liter of sulphuric acid at a temperature of about 45 C. to form a water-soluble. cellulose xanthate thread, cutting said thread into staple fibers of cellulose xanthate, mechanically opening said fibers, introducing said fibers into an acidifying bath containing about 10 grams per liter of sulphuric acid to decompose said xanthate staple fibers directly into curled, unfelted, full-bodied staple fibers of regenerated cellulose and then after-treating said fibers.

3. A process of producing curled, unfelted, fullbodied staple fibers which comprises extruding a viscose solution having a cellulose content of about 8% and an alkali content of about 5% and having a ripeness of about 1.2 degrees Hottenroth through a spinning nozzle into a spin bath containing about 300 grams per liter of sodium sulphate and about 10 grams per liter of sulphuric acid at a temperature of about 45 C. to form a water-solublecellulose xanthate thread, cutting said thread into staple fibers of cellulose xanthate, mechanically opening said fibers, introducing said fibers into an acidifying bath containing about 10 grams per liter of sulphuric acid to decompose said xanthate staple fibers directly into curled, unfelted, full-bodied staple fibers of gigenerated cellulose and then after-treating said ers.

4. A process of producing curled, unfelted, fullbodied staple fibers which comprises extruding a viscose solution having a cellulose content of about 8% and an alkali content of about 5% and having a ripeness of about 3 degrees Hottenroth through a spinning nozzle into a spin bath containing about'300 gram per liter of sodium sulphate and about 10 grams per liter of sulphuric acid at a temperature of about 45 C. to form a water-soluble cellulose xanthate thread, cutting said thread into staple fibers of cellulose xanthate, mechanically opening said fibers, introducing said fibers into an acidifying bath containing about 30 grams per. liter of sulphuric acid to decompose said xanthate staple fibers directly into curled, unfelted, full-bodied staple fibers of regenerated cellulose, and then after-treating said fibers.

JOHANN JOSEPH STOECKLY. 

